PLANT BREEDING Jo 
There is another case of a different kind. Sometimes the hybrid 
character is different from the character of the parents, even though 
the exact parental characters are reproduced by segregation in succeed- 
ing generations. The commercial carnation form is the result of cross- 
ing the single carnation with the huge worthless doubles called 
“busters.” Reproduced by seed the commercial carnation throws both 
singles and busters, showing that segregation of the parental characters 
takes place; but as these plants are easily reproduced by cuttings, and 
the cuttings are all of the commercial type, sexual reproduction is only 
resorted to for the sake of producing new varieties. Another common 
phenomenon attending hybridization is sterility. Many very beautiful 
flowers produce no seed at all. This is even an advantage in some cases, 
because the plants flower more profusely than if they were spending 
their energies in the production of seed. Here again, cuttings are re- 
sorted to to reproduce the hybrid, or, as in the case of seedless oranges, 
the cuttings are grafted into an older rootstock instead of being rooted. 
I stated at the beginning that there were two other classes of 
hybridization phenomena, the production of fixed first-generation 
hybrids and the production of blend hybrids. It is probable in the last 
analysis that the true explanation of these cases is the same; so we will 
consider them together. It is believed by many that there are kinds of 
inheritance other than Mendelian, that is, inheritance where no segrega- 
tion occurs. Far be it from me to deny this; I simply state the fact 
that there are no exact data extant proving other kinds of inheritance. 
Such data may be found, but it is useless to speculate upon other laws 
without such evidence. There are several cases in which either new 
characters that breed true or blended characters that breed true 
appear to have been formed, but they have not been studied with 
sufficient care for an analysis of their mode of inheritance to be accurate 
and final. It is in crosses between true species that hybrids have been 
formed seemingly as constant and uniform as their parent species. Janc- 
zewsky has produced several such hybrids. Perhaps the most famous, 
however, are the blackberry-raspberry crosses first produced by the late 
BK. S. Carman, editor of the Rural New-Yorker and later by Luther Bur- 
bank and others. Several hybrids having a commercial value have been 
made in this genus (Rubus), and all of them reproduce approximately 
true from seed. These are the facts and show what may sometimes be 
expected by hybridizers when crossing true species; but I wish to point 
out that this does not necessarily mean that we are dealing with a new 
mode of inheritance. Bramble species produce seedlings that are quite 
variable and in which the variations are extremely difficult to describe: 
there is, therefore, no exact information as to the relative variability of 
the hybrid seedlings as compared to that of the two parents. It may be 
said, then, that it is yet unknown whether there is partial segregation. 
